Octadecagon
| Regular octadecagon | |
|---|---|
A regular octadecagon | |
| Type | Regular polygon |
| Edges and vertices | 18 |
| Schläfli symbol | {18}, t{9} |
| Coxeter–Dynkin diagrams | |
| Symmetry group | Dihedral (D18), order 2×18 |
| Internal angle (degrees) | 160° |
| Properties | Convex, cyclic, equilateral, isogonal, isotoxal |
| Dual polygon | Self |
In geometry, an octadecagon (or octakaidecagon) or 18-gon is an eighteen-sided polygon.